In April 1981 violent clashes between black youths and police in Brixton, south London, shocked the nation and ultimately changed policing and race relations in Britain forever.

Twenty-five years on, a former police officer and a protester went back to the streets of Brixton for a BBC documentary marking the anniversary.

They recall the violence and reflect on how much the Brixton riots had altered the course of their own lives.

ALEX WHEATLE, FORMER BRIXTON PROTESTER

The riots inspired Alex Wheatle to become a novelist

Born in South London of Jamaican parents, Alex Wheatle was 18 at the time of the riots.

He was among thousands of teenagers throwing bricks and bottles at police on Railton Road, which became known as "the Front Line".

Now he is an established writer and father of three still living in south London.

His award-winning novel East of Acre Lane, published in 2001, was inspired by the Brixton riots.

Last year he went back with a film crew to re-live the experience for a documentary marking the 25th anniversary.

"When I was standing on Railton Road these memories all flooded back to me," he told the BBC News website. "I could remember almost every minute of that day, even what I had for breakfast - it's so vivid in my mind."

He was filmed re-enacting his own movements that day, how his anger mounted until he joined the crowds, looking for something, anything to throw at the police - and then he described a moment of hesitation.

Black kids were being purged off the streets, they were being beaten up in cells

Alex Wheatle

"The streets were just full of bricks, mortar, stones, smashed bottles, a carpet. And the police were lined up as far as the eye could see sipping on the soups and teas and coffees out of polystyrene cups.

"And that was the first time I realised these guys - they've got homes to go to, they might have family, brothers, sisters, mothers probably worrying about them."

But he felt justified in taking part because "black kids were being purged off the streets, they were being beaten up in cells. The establishment had to acknowledge that. I stood up and I fought with them."

"The dynamics of the area have changed. Brixton used to be 80%-90% Afro-Caribbean. Now it's a big melting pot of Portuguese, East Africans, New Zealanders.

"There's less of a sense of menace than there used to be. Back then, you could feel a hint of danger, which made it attractive to some people. But now you've got wine bars, the Academy, the Fridge [nightclubs]. It's turning into a Notting Hill, it's a cool place to go."

Wheatle says the future for black people in Britain looks brighter than it did 25 years ago.

"Now there is some hint of hope. Back in 1981, I felt I had no hope at all. When I look at my children, I know they have avenues, they have potential."

"I can't speak for other people but for me, the riots, in a way, did change my life - I became an author.

"And it made the government acknowledge there was a problem, because before we were just ignored."

ROGER FULLER, FORMER POLICE CONSTABLE

Former police officer Roger Fuller is now an expert on managing conflict

Roger Fuller was a 30-year-old constable with the Metropolitan Police at the time of the riots.

He retired from the force nine years ago and now runs a company that trains security staff in conflict management.

Reliving the events of April 1981 for the BBC documentary was a tough call. He had not been back to Brixton for many years and found standing on Railton Road "quite emotional".

"Your mind tends to block out certain memories," he said. But he acknowledged, "The riots opened my eyes to cultural differences. That's why I do conflict management now."

On 11 April he had been called in from his base in Roehampton, south-west London, to help out his colleagues in Brixton.

People were setting alight. It was quite horrendous

Roger Fuller

"We were hearing police officers screaming for assistance," he told the film-makers.

"To be quite honest I had a cold chill that came over me. People were cut off. People were calling for help, so it did start to build up a picture for us before we got there.

"As we moved up to Railton Road, that's when these people saw us and we became their targets.

"Bricks started to rain down, we had no shields. I remember at one stage grabbing hold of a dustbin lid. We were retreating. We had to for our own safety."

When they were eventually given riot shields, the police did not know how to use them properly and found themselves locked in a rigid line and even more vulnerable to attack. One rioter, he said, came right up to the line of shields, tipped some whisky over an officer and tried to set light to him.

"I had traffic officers to one side of me, admin staff who'd never seen a shield and women police officers who weren't trained to use a shield in those days, so all they were doing was hiding behind their shields while we really should have gone forward."

As the violence escalated young men started throwing Molotov cocktails - a sight never before seen in Britain.

"The petrol bomb was hitting you flat on, the petrol was going underneath the shields and then coming up and burning the foam underneath.

"People were screaming and shouting. People were setting alight. It was quite horrendous."

The riot finally ended when police commandeered a fire brigade hose and aimed it at rioters. But the end of the disturbances was, for Pc Fuller, the beginning of months of "after-stress".